The present invention relates to a gas flow rate measuring device and a gas flow rate measuring method for measuring mass flow rate of measuring object gas.
A gas flow rate measuring device, that is available to be adopted as an air flow meter of an automotive engine, is known in the art as disclosed in a Japanese Application Laid-Open No. 2001-194202. The gas flow rate measuring device has a heater located at a center of a sensor element to heat temperature measuring resistors, disposed both the upstream and the downstream of the heater, to allow the flow rate of measuring object gas to be detected as mass flow rate passing per unit time based on a difference between resistance values detected during flow of measuring object gas over the sensor element.
Thus, if no variation takes place in composition of measuring object gas with a change with the passage of time, such as when measuring object gas prevails in an intake manifold of an automotive engine, the flow rate of measuring object gas can be accurately measured with such a thermal type flow sensor.